Exercise (remove use of 0000-00-00 00:00:00)

app/Migrations/Schema/V111/Version111.php

@@ -71,7 +71,6 @@ class Version111 extends AbstractMigrationChamilo
         $this->addSql('ALTER TABLE c_lp CHANGE publicated_on publicated_on DATETIME');
         $this->addSql('ALTER TABLE c_lp CHANGE expired_on expired_on DATETIME');
 
-
         $this->addSql('UPDATE TABLE c_quiz SET start_time = "" WHERE start_time = "0000-00-00 00:00:00"');
         $this->addSql('UPDATE TABLE c_quiz SET end_time = "" WHERE end_time = "0000-00-00 00:00:00"');
 

main/admin/user_move_stats.php

@@ -374,7 +374,7 @@ if (isset($_REQUEST['load_ajax'])) {
 	                                       qualification    = '".$parent_data['qualification'] ."',
 	                                       parent_id    = '',
 	                                       qualificator_id  = '',
-	                                       date_of_qualification    = '0000-00-00 00:00:00',
+	                                       date_of_qualification    = '',
 	                                       session_id   = ".$new_session_id;
                                     $rest_insert     = Database::query($sql_add_publication);
                                     if ($debug) echo ($sql_add_publication);

main/exercice/exercise_submit.php

@@ -734,7 +734,7 @@ if ($limit_time_exists) {
         $permission_to_start = true;
     }
     if ($_SERVER['REQUEST_METHOD'] != 'POST') {
-        if ($objExercise->end_time != '0000-00-00 00:00:00') {
+        if (!empty($objExercise->end_time)) {
             $exercise_timeover = (($time_now - $exercise_end_time) > 0) ? true : false;
         } else {
             $exercise_timeover = false;

main/inc/lib/notebook.lib.php

@@ -243,8 +243,7 @@ class NotebookManager
         }
 
         // Database table definition
-        $t_notebook = Database :: get_course_table(TABLE_NOTEBOOK);
-        $order_by = "";
+        $t_notebook = Database :: get_course_table(TABLE_NOTEBOOK);        
         if ($_SESSION['notebook_view'] == 'creation_date' || $_SESSION['notebook_view'] == 'update_date') {
             $order_by = " ORDER BY " . $_SESSION['notebook_view'] . " $sort_direction ";
         } else {
@@ -255,7 +254,7 @@ class NotebookManager
         $session_id = api_get_session_id();
         $condition_session = api_get_session_condition($session_id);
 
-        $cond_extra = ($_SESSION['notebook_view'] == 'update_date') ? " AND update_date <> '0000-00-00 00:00:00'" : " ";
+        $cond_extra = ($_SESSION['notebook_view'] == 'update_date') ? " AND update_date <> ''" : " ";
         $course_id = api_get_course_int_id();
 
         $sql = "SELECT * FROM $t_notebook